In recent years, a one-stage conversion method has been proposed in which power factor control of input AC current and output power control are achieved at the same time in one power conversion device. As a conventional power conversion device of one-stage conversion type, a converter circuit for charger will be described below.
The converter circuit for charger is provided with: a half-bridge rectification circuit composed of two diodes; a capacitor connected in parallel to both ends of the half-bridge rectification circuit; a full-bridge circuit composed of four switch elements and formed by connecting, in parallel, both ends of a first half-bridge circuit composed of two switch elements (1) and (2) and a second half-bridge circuit composed of two switch elements (3) and (4), to both ends of the capacitor; a reactor provided between one end of an AC power supply the other end of which is connected to the connection point between the switch elements in the first half-bridge circuit, and the connection point between the diodes in the half-bridge rectification circuit; a primary coil of a high-frequency transformer connected between the connection points between the switch elements in the first and second half-bridge circuits; four drive circuits connected to the four switch elements; and a control circuit, thus forming a primary circuit of a converter. The control circuit performs ON/OFF control alternately for a group of the switch elements (1) and (4) and a group of the switch elements (2) and (3) in the full-bridge circuit composed of the four switch elements.
Further, a full-bridge rectification circuit connected in parallel to a secondary coil of the high-frequency transformer, and a capacitor connected in parallel to both ends of the full-bridge rectification circuit, form a secondary circuit of the converter, which rectifies high-frequency power generated by the primary circuit and charges a battery (for example, see Patent Document 1).